1. Technical Field
The present disclosure relates to a non-orthogonal transmission technology for a communication system, and more specifically, to a non-orthogonal transmission technology which reduces complexity of a receiving end.
2. Related Art
A communication system may comprise a core network (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), a mobility management entity (MME), etc.), a base station (e.g. a macro base station, a small base station, a relay, etc.), a terminal, and the like. Communications between the base station and the terminal may be performed using various radio access technologies (RATs) such as 4G communication technology, 5G communication technology, wireless broadband technology (WiBro), wireless local area network (WLAN), wireless personal area network (WPAN) technology, etc.
When uplink data exist in the terminal, the terminal may transmit a message requesting uplink transmission scheduling to the base station. Then, the base station may receive the message requesting uplink transmission scheduling from the terminal, and transmit an uplink grant to the terminal in response to the message. When the uplink grant is received from the base station, the terminal may transmit uplink data to the base station using a resource allocated by the base station.
When autonomous transmission (e.g., non-orthogonal transmission) is supported in a communication system, a terminal may transmit uplink data to a base station without an uplink grant. For example, the terminal may select a resource in a preconfigured resource pool and transmit uplink data to the base station using the selected resource. Here, the preconfigured resource pool may be shared by the base station and a plurality of terminals. Since the terminal does not know resources used by other terminals, the resource selected by the terminal from the preconfigured resource pool may be overlapped with the resources used by other terminals. In this case, a plurality of terminals may transmit uplink data using the same resource, thereby causing a transmission collision.
Meanwhile, since the base station does not know the resource selected by the terminal from the preconfigured resource pool, the base station should monitor all resources belonging to the preconfigured resource pool in order to receive the uplink data from the terminal. Accordingly, complexity of a receiving end may be increased in the case that the autonomous transmission (e.g., non-orthogonal transmission) is performed.